H I S C A P T O R S. 71 



Greenland Mendusse. Scoresby's Arithmetic. 



basis of subsistence for the numerous tribes of 

 the Arctic world is found in the genus medusa, 

 which the sailors graphically describe as sea- 

 blubber. The medusa is a soft, elastic, gelat- 

 inous substance, specimens of which may be 

 seen lying on our own shores, exhibiting no signs 

 of life, except that of shrinking when touched. 

 Beyond the Arctic Circle it increases in an ex- 

 traordinary degree, and is eagerly devoured by 

 the finny tribes of all shapes and sizes. By far 

 the most numerous, however, of the medusan 

 races are of dimensions too small to be discov- 

 ered without the aid of the microscope, the ap- 

 plication of which instrument shows them to be 

 the cause of a peculiar color, which tinges a 

 great extent of the Greenland Sea. This color 

 is olive-green, and the water is opaque com- 

 pared to that which bears the common cerulean 

 hue. 



" These olive waters occupy about a fourth of 

 the Greenland Sea, or above twenty thousand 

 square miles, and hence the number of medusan 

 animalcula which they contain is far beyond 

 calculation. Mr. Scoresby estimates that two 

 square miles contain 23,888,000,000,000,000 ; 

 and as this number is beyond the range of hu- 



